Oxidative dehydrogenation with promoted barium ferrite catalysts

ABSTRACT

Catalysts comprising ferrites of iron modified with oxides of cerium, zinc, manganese and lead and ferrites of barium modified with oxides of zinc, manganese and lead and a process of oxidative dehydrogenation of organic compounds in the presence of these catalysts compositions and cocatalyst such as chlorine.

United States Patent [19 1 Hinkson etal.

[ Dec. 3, 1974 OXIDATIVE DEHYDROGENATION WITH PRUMOTED BARIUM FERRITECATALYSTS lnventors: Robert E. Hinkson; William H.

Taylor, both of Houston, Tex,

Assignee: Petro-Tex Chemical Corporation,

Houston, Tex.

Filed: Sept. 26, 1973 Appl. No.: 400,755

Related [1.5; Application Data Continuation-impart of Ser. No. 249,963,May 3, 1972, abandoned.

in. ct. C07c 5/18 Field of Search 260/680 E, 683.3

References Cited UNITED STATES PATENTS 3,303,235 2/1967 CIOCC et al.260/6833 US. (Cl..... 260/680 E, 252/471, 252/473,

Christmann 260/680 E Hwa et al. 260/680 E Croce ct al' 260/680 E Croceet 260/680 E Croce ct al 260/680 E Croce et a1 260/680 E PrimaryExaminerPaul M. Coughlan, Jr. Attorney, Agent, or Firm N. Elton DryABSTRACT 5 Claims, N0 Drawings OXIDATIVE DEHYDROGENATION WITH PROMOTE!)BARIUM FERRITE CATALYSTS CROSS REFERENCE BACKGROUND OF THE INVENTION 1.Field of the Invention This application relates to the oxidativedehydrogenation of organic compounds in the presence of oxygen,

halogen and a particular catalyst. The catalyst of this inventioncomprises those selected from the group consisting of iron ferrite whichhas been modified by the addition thereto of a metal oxide comprisingthe oxides of cerium, zinc, manganese and lead and barium ferrite whichhas been modified by the addition thereto of a metal oxide comprisingtheoxides of zinc, manganese and lead.

2. Description of the Prior Art US. Pat. No. 3,303,234 discloses theoxidative dehydrogenation of organic compounds with a catalystcomprising barium ferrite. The oxidative dehydrogenation of organiccompounds with catalyst comprising ferrites is also disclosed in US.Pat.- Nos. 3,270,080; 3,284,536; 3,303,235; 3,303,236; 3,303,238;

3,342,890; 3,420,911; 3,420,9l2;3,428,703 and 3,440,229.

SUMMARY OF THE INVENTION- This invention relates to improved catalystcompositions and a process for oxidative dehydrogenation of organiccompounds using the improved catalyst. The improved catalystcompositions comprise ferrites of iron having combined therewith as acatalystmodifier a metal oxide selected from the group consisting of CeOZnO, MnO and PbO or mixtures of these oxides and ferrites of bariumhaving combined therewith as a catalyst modifier a metal oxide selectedfrom the group consisting of ZnO, MnO and PhD or mixtures of theseoxides. This invention also relates to a process where these improvedcatalyst compositions are used in an oxidative dehydrogenationprocess'where oxyge, an organic compound and a halogenare fed to areactor containing the improved catalyst compositions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS tives thereof. One of theprimary objectives in catalyst development is to produce more activecatalysts which retain a high degree of selectivity of the productsdesired. Such catalysts generally provide improved processes resultinginhigher yields of the desired product.

' l The catalyst of the present invention comprise iron ferrite in whichthere has been incorporated a promotin'g amount of a metal oxideselected from the group consisting ofCeO ZnO, MnO PhD and mixturesthereof, and barium ferrite in which there has been in corporated apromoting amount of a metal oxide selected from the group consistingofZnO, MnO PhD and mixtures thereof. The improved process/of the presentinvention comprises feeding oxygen or an oxypresent ina minorproportion. Thus, the catalyst com-- position of the present inventioncan contain up to 45 percent by weight cerium oxide, zinc oxide,manganese oxide, lead oxide, or mixtures thereof with the remainderbeing essentially iron ferrite, barium ferrite or mixtures thereof.Generally, it has been found preferable to incorporate from 0.35 to 1.3moles of the metal oxide modifier per mole of iron oxide or barium oxidein the catalyst composition.

The organic compounds to be dehydrogenated according to the process ofthis invention are hydrocarbons of four to seven carbon atoms andpreferably hy-" drocarbons selected from the group consisting of satu-"rated hydrocarbons, cycloaliphatics, monoolefins, diolefins and mixturesthereof of four to five or six car bon atoms having a straight chain ofat least four car bon atoms. Examples of preferred feed materials arebutene-l, cis-butene-Z, trans-butene-Z, 2-methyl butene-l, 2-methyl.butene-2, 2-methyl butene-3, nbutane, butadiene-l,3, methyl butane,cyclohexane, cyclohexene, 2-methyl pentene-l, 2-methyl pentene2 andmixtures thereof. For example, n-butane may be converted to a mixture ofbutene-l and butene-2 or may be converted to a mixture of butene-l,butene-2 and/or butadiene-l,3. A mixture of n-butane and butene-2 may beconverted to butadiene-l,3 or to a mixture of butadiene-l ,3 togetherwith some butene-Z and butene-i. Vinylacetylene may be present as aproduct, particularly when butadie'ne-l,3 is used as a feedstock. Thus,the process of this invention is useful in converting hydrocarbons toless saturated hydrocarbons of the same number of carbon atoms. Themajor proportion of the hydrocarbons converted'will be to less saturatedhydrocarbons of the same number of carbon atoms.

Particularly, the preferred products are butadiene-l,3'

tion of gasoline from higher hydrocarbons either therma] or' catalyticcrackinga hydrocarbon stream containing predominantly hydrocarbons offour carbon atoms may be produced and comprise a mixture of butenestogether with butadiene, butane, isobutane, isobutylene and otheringredients in minor'amounts. These and other refinery by-products whichcontain normal, ethylenically unsaturated hydrocarbons are useful asstarting materials for the present process. Although various mixtures ofhydrocarbons-are useful, the preferred hydrocarbon feed contains atleast50 weight percent of a hydrocarbon selected from the groupconsisting of butene-l, butene-Z, n-butane, butadiene-l,3, 2-methylbutene-l, Z-methyl butene-Z; 2-methyl butene-3 and mixtures thereof, andmore preferably contains'at least weight percent, of one or more ofthese hydrocarbons (with both of these percentages being based onthe'total weight of the organic composition of the feed to the reactor).Any remainder may be, for example, essentially aliphatic hydrocarbons.This invention is particularly useful to provide a process whereby themajor product of the hydrocarbon converted is a dehydrogenatedhydrocarbon product having the same number of carbon atoms as thehydrocarbon fed. v

Diluents such as nitrogen, helium, or other gases 5 which are notdehydrogenated or which are dehydrogenated only to. a limited extent maybe used in the process of the present invention. Mixtures of diluentsmay ylbromide; aromatic halides such as benzyl bromide;

halohydrins such as ethylene bromohydrin; halogen substituted aliphaticacids suchas bromoacetic acid;

I ammonium iodide; ammonium bromide; ammonium chloride; organic aminehalide salts such as a methyl amine hydrobromide; and the like. Mixturesof various sources of halogens. may be used. The preferred sources ofhalogen are iodine, bromine and chlorine and compounds thereof such ahydrogen bromine, hydrogen iodide, hydrogen chloride, ammonium bromide,ammonium iodide, ammonium chloride, alkyl halides of one to six carbonatoms and mixtures thereof with the chloride compounds beingparticularly preferred, with excellent results being obtained from theuse of chlorine or hydrogen-chloride. When terms such as halogenliberating materials or halogen materials are used in the specificationand claims, this includes any source of halogen such as elementalhalogen, hydrogen halides or ammonium halides. The amount'of halogencalculated as elemental halogen, may be as little as about 0.000! orlessmole of halogen per mole of the hydrocarbon compound to bedehydrogenated to as much as 0.2 or 0.5.moles of halogen per mole ofhydrocarbon compound to be dehydrogenated. The preferred range-is from0.000l to. 0.09- moles of halogen per mole of hydrocarbon to bedehydrogenated.

Oxygen will be present in the reaction zone in an amount within therange of 0.2 to 2.5 moles of oxygen per mole of hydrocarbon to bedehydrogenated. Generally, better results may be obtained if the oxygenconcentration is maintained between about 0.25 and about 1.6 moles ofoxygen per mole of hydrogen to be dehydrogenated, such as between 0.35and 1.3 moles of oxygen per mole of hydrocarbon to be dehydrogenated.

The oxygen may be fedto the reactor as pure oxygen,

as air, asoxygen-enriched air, oxygen mixed with diluents, etc. Based onthe total gaseous mixture entering the reactor, the oxygen normally willbe present in an amount from about 0.5 to-25 volume percent of the totalgaseous mixture, and more usually will be present in an'amount'fromabout l to 50 volume percent of the total. Thetotal amount of oxygenutilized may be introduced into the gaseous mixture entering thecatalytic Zone or it can be added in increments, such as differentsections of the reactor. The above described proportions of oxygenemployed are based on the total amount of oxygen used. The oxygen may beadded dibe between about 25 and 6,400, and excellent results rectly tothe reactor or it may be premixed, for example, with a diluent or steam.

The temperature for the dehydrogenation reaction will be greater than400 C, and the maximum temperature in the reactor may be about 750 C orperhaps higher under certain circumstances. Excellent results areobtained within the range of about 500 C to 600 C. The temperatures aremeasured at the maximum temperature in the reactor.

The dehydrogenation reaction may be carried out at atmospheric pressure,super-atmospheric pressure or at sub-atmospheric pressurejThe totalpressure of the system will normally be about or in excess ofatmospheric pressure although sub-atmospheric pressure may alsodesirably be used. Generally, the total pressure will be between about 4psia and about or psia. Preferably the total pressure will be less thanabout 75 psia and excellent results will be obtained at aboutatmospheric pressure.

Conveniently, the oxygen may be added as air with any nitrogen or othergas acting as a diluent for the system. Mixtures of diluents may beemployed. Volatile drogenated if steam is employed. The functions of thesteam are several fold, as described in the patent references mentionedhereinbefore. However, the steam does act as a diluent. Diluentsgenerally may be used in the same quantities specified for the steam.Excellent results are obtained when the gaseous composition fed to thereactor consists essentially of hydrocarbons, inert diluents and oxygenas the sole oxidizing agent.

The gaseous reactants may be conducted through thereaction chamber at afairly wide range of flow rates. The optimum flow rate will be dependentupon such variables as the temperature of reaction, pressure, particlesize and whether a fluid bed or a fixed bed reactor is utilized.Desirable flow rates may be established by one skilled in the art.Generally, the flow rates will be within the range of about 0.10 to 25liquid volumes of the hydrocarbon to be dehydrogenated per volume ofreactor containing catalyst per hour (referred to as LHSV), wherein thevolumes of hydrocarbon are calculated at standard conditions of 25 C and760 millimeters of mercury. Usually, the LHSV will be between 0.15 andabout 5 or 10. For calculation, the volume of reactor containingcatalyst is that volume of reactor space excluding the volume displacedby the catalyst for example if a reactor has a particular volume ofspace flow velocity (GHSV) is the volume of the hydrocarbon to bedehydrogenated in the form of vapor calculated under standard conditionsof 25 C and 760 millimeters of mercury per volume of reactor spacecontaining catalyst per hour. Generally, the GHSV will have beenobtained between about 38 and 3,800. Suitable contact times are,forexample, fromabout 0.001

or higher to about 5 or 10 seconds with particularly good results beingobtainedbetween 0.01 and 3 seconds. The contact time is the calculateddwell time of the reaction mixture in the reaction zone, assuming themoles of product mixture are equivalent to the moles of feed mixture.For the purpose of calculation of residence times, the reaction zone isthe portion of the reactor containingcatalyst.

As mentioned hereinbefore, the catalyst composition of the presentinvention comprises iron ferrite or barium ferrite combined togetherwith the specified metal oxide selected from the group consisting of CeOZnO, Win0 PbO and mixtures thereof. Based on the total active catalystcomponents, the metal oxide will be present in a range of 0.3 to 1.3moles to'mole-of the ferrite component. The catalyst composition canalso include inert binding agents and fillers, but these will notordinarily exceed about 50 percent or 60 percent by weight of thecatalytic composition including active catalyst components and inertbinding agents or fillers. The catalyst will be by definition present ina catalytic amount. The amount of catalyst ordinarily will be greaterthan ten square feed of catalyst surface per cubic foot of reaction zonecontaining catalyst. The term catalyst is meant to mean total activecatalyst components and does not include inert binding agents orfillers. Of course, the amount of catalyst may be much greater,particularly when irregular surface catalyst are used. When the catalystis in the form of particles, either supported or unsupported, the amountof catalyst surface maybe expressed in terms of the sur- I face area perunit weight of any particular volume of catalyst particles. The ratio ofcatalyst surface to weight will be dependent upon several factors,includ ing the particle size distribution, apparent bulk density of theparticles, the carrier etcf Typical values for the surfaced to weightratio are such as'about /2 to 200 square meters per gram although higherand lower values may be used.

The dehydrogenation reactor may be of the fixed bed of fluid bed type.Conventional reactors for the production of unsaturated hydrocarbons aresatisfactory. Excellent results have been obtained by packing thereactor with catalystparticles as the method of introducing is catalyticor is coated with catalytic material. Other methods may be utilized tointroduce the catalytic sur-' face such as by the use of rods, wires,mesh, or shreds and the like of catalytic material.

In the following examples will be found specific embodiments of theinvention and details employed in the practice of the invention. Percentconversion refers to the moles of hydrocarbon consumed per 100 moles ofhydrocarbon fed to the reactor, percent selectivity refers to the molesof product formed per 100 moles of hydrocarbon consumed, and percentyield refers to the moles of product formed per I00 moles of hydrocarbonfed. All other percentages are be weight unless ex pressed otherwise.

EXAMPLES ll-5 in the amounts shown in Table I. The barium ferrite orbarium ferrite containing the metal oxide was coated on 4 to 8 meshalumina pellets in an amount of roughly 30 percent of weight of thebarium ferrite or barium ferrite incorporating the metal oxide based onthe total .weight. In each of the Examples l-5, n-butane wasdehydrogenated at atmospheric pressure in a Vycor glass reactorcontaining therein a cc. catalyst bed supported on a 1-inch deep layerof Rashig rings. The reactants, n-butane, oxygen, nitrogen and chlorinewere introduced into the top of the glass reactor, and the effluentgases were withdrawn from the bottom of the reac tor. Samples of theeffluent gases were analyzed in a vapor chromatograph.

The mixture of n-butane, oxygen, nitrogen and chlorine was fed to thereactor in an amount of 1.3 moles of oxygen, 0.3 moles of chlorine and15 moles of nitrogen per mole of nbutane. The LHSV was 0.25 and themaximum temperature in the reactor was 580 C. The

results obtained in Examples 1-5 are shown in Table l.

Present in amount of 25 wcighlpcrcent based on total weight of BaFe,Oand promoter. Mixture of 15 weight percent PM). 10 weight percent ZnOwith mixture prcsentinumounl of 25 Weight percent based on total Baferrite and oxide modifier.

the catalytic surface. The catalytic surface may 'bein troduced assuch'or it may be depositied on a carrier by methods known in the artsuch as by preparing an aqueous solution or dispersion of a catalyticmaterial and mixing the carrier with the solution or dispersion untilthe active ingredients are coated on the carrier. If a carrier isutilized, very useful carriersare silicon carbide, pumice and like. Whencarriersare used, the amount-of catalyst on the carrier will generallybe between about 5 to 75 weight percent of the total weight of activecatalytic material plus carrier. Another method for introducing therequired surface is to utilize as areactor a small diameter tube whereinthe tube wall EXAMPLES 6 8 The procedures of Examples 1 5 were repeatedwith the exception that iron ferrite, Fe O was used in Example 6 as thecatalyst and Fe O containing CeO was used in Example 7, Fe O containingPbO and ZnO was used in Example 8. Otherwise, the conditions and processsteps were identical to those of Examples 1-5.

The results obtained from Examples 6-8 are shown in from the groupconsisting of ZnO, MnO PbO and mix- Table II. tures thereof TABLE 11Percent Percent Total Percent Yield of Yield of Percent Example CatalystPromoter Conversion Butenes Butadiene Yield D 6 R2 None 82 2s 2s 56 7 FeO CeO* 83 31 32 63 8 Fe O, PbO/ZnO** 78 28 35 63 Present in amount of 25weight percent based on total weight of Fe ferrite and modifier."Mixture of 15 weight percent PhD and 10 weight percent ZnO with themixture being present in amount or 25 weight percent based on totalweight of Fe ferrite and the mixture of PbO and ZnO.

Examples 7 arid 8 showed increased yields of butadi- 2. A processaccording to claim 1 wherein the hydroene as well as total yields ofbutenes and butadiene in carbon is selected from the group consisting ofncomparison to the control Example butane, n-butene and mixturesthereof.

We a m 3. A process according to claim 2 wherein the tem- 1. A processfor the oxidative dehydrogenation of hyperature i f 500 C t 600 C,drocarbons ha ing Ou Seven carb a qm av 4. A process according to claimit wherein said hya Straight chain of at 163st 4 carbon atoms. toproduce drocarbon is selected from the group consisting of satulesssaturated hydrocarbons of the same number of carrated hydrocarbon-s,monoolefins, di l fi and bon atoms which comprises contacting, at atemperatul-es th f i mm of greater than Said hydrocarbon a halo 5. Aprocess according to claim 4 wherein the hydrog halogen Compound whichwould liberate halo carbon is selected from the group consisting ofbutenegen under the conditions Of reaction and from 0.2 t() I, i-butene-2 trans-butene-2 pentene-] gig- 2.5 moles of oxygen per mole ofsaid hydrocarbon with m g transmemeneq, 2 b q 2- a catalyst for thedehydrogenation consisting essenh l b q 2- butenegt, 2. 1

tially Of barium ferrite and 0.35 to moles per mole gene-l, 2-methy]pentene-g, 2..methy] pentene-3 and of barium ferrite of a metal oxidemodifier selected mixtures th f

1. A PROCESS FOR THE OXIDATIVE DEHYDROGENATION OF HYDROCARBONS HAVINGFOUR TO SEVEN CARBON ATOMS HAVING A STRAIGHT CHAIN OF AT LEAST 4 CARBONATONS TO PRODUCE LESS SATURATED HYDROCARBONS OF THE SAME NUMBER OFCARBON ATOMS WHICH COMPRISES CONTACTING AT A TEMPERATURE OF GREATER THAN400*C., SAID HYDROCARBON, A HALOGEN OR HALOGEN COMPOUND WHICH WOULDLIBERATE HALOGEN UNDER THE CONDITIONS OF REACTION AND FROM 0.2 TO 2.5MOLES OF OXYGEN PER MOLE OF SAID HYDROCARBON WITH A CATALYST FOR THEDEHYDROGENATION CONSISTING ESSENTIALLY OF BARIUM FERRITE AND 0.35 TO 1.3MOLES PER MOLE OF BARIUM FERRITE OF A METAL OXIDE MODIFIER SELECTED FROMTHE GROUPS CONSISTING OF ZNO. MNO2, PBO, AND MIXTURES THEREOF.
 2. Aprocess according to claim 1 wherein the hydrocarbon is selected fromthe group consisting of n-butane, n-butene and mixtures thereof.
 3. Aprocess according to claim 2 wherein the temperature is from 500* C to600* C.
 4. A process according to claim 1 wherein said hydrocarbon isselected from the group consisting of saturated hydrocarbons,monoolefins, diolefins, and mixtures thereof.
 5. A process according toclaim 4 wherein the hydrocarbon is selected from the group consisting ofbutene-1, cis-butene-2, trans-butene-2, pentene-1, cis-pentene-2,trans-pentene-2, 2-methyl butene-1, 2-methyl butene-2, 2-methylbutene-3, 2-methyl pentene-1, 2-methyl pentene-2, 2-methyl pentene-3 andmixtures thereof.